1. Field of the Invention
This invention relates to a dripless coupler for coupling to and uncoupling from two hydraulic functions while preventing spillage of oil during the uncoupling operation and requiring limited pressure to be disconnected.
2. Description of the Prior Art
Numerous hydraulic couples are available on the market today which can be used to connect hydraulic lines together. Such couplers are used in a wide variety of applications including use on agricultural and industrial type tractors wherein a tractor is hydraulically connected to a towed implement. One of the major drawbacks with the current hydraulic couplers is that they tend to leak oil while being disconnected. This leaked oil flows down the rear of the tractor and attracts foreign matter such as dirt. The presence of a dirty oily surface on the rear of the tractor is undesirable because the dirt has the potential of entering the hydraulic lines and contaminating them.
One coupler which partially solved this problem was taught by applicant in an earlier patent application, U.S. Pat. No. 4,303,098 which is made a part of this application and is incorporated by reference. This particular coupler was easy to disconnect and allowed only a limited amount of spillage during the uncoupling process. Other couplers which prevent dripping or spillage during the uncoupling process were described in the Aug. 11, 1977 issue of "Machine Design" magazine on pages 86-90. This article, which was written by an engineer at Snap-Tite, Inc., describes couplers that have spillage rates of less than several cubic centimeters during the uncoupling operation. However, the acceptability of these couplers has been minimal because a significant amount of pressure is required to disconnect. These couplers also differ in physical design and construction with most using sliding seals versus flush poppet seals. Now a dripless coupler has been invented which prevents spillage of oil during the uncoupling operation while requiring only limited pressure to be disconnected.